Ahmet Can Altunişik

• Professor
• Professor (Associate) at Karadeniz Technical University

The February 6, 2023, doublet earthquake in Kahramanmaraş, Türkiye, known for its multi-fault rupture, caused widespread destruction and affected numerous buildings across 17 provinces. This research focused on the utilization of machine learning (ML) models for the classification of an extensive earthquake-induced building damage dataset collected...

This study explores the application of FRP strengthening for enhancing the performance and resilience of fire-damaged concrete elements subject to different cooling regimes, with a focus on their effectiveness in restoring structural capacity and durability following fire exposure. To achieve this aim, 90 concrete cylinder specimens were produced a...

An earthquake sequence comprising three major events with moment magnitudes of 7.7 (mainshock), 6.6 (aftershock), and 7.6 (mainshock) hit the southeastern regions of Turkiye on February 6, 2023. Eleven provinces were directly affected by these events, and thousands of buildings either collapsed or were heavily damaged. Post-event reconnaissance ef...

Structural health monitoring (SHM) has been widely employed in civil infrastructures for a number of years. Real-time monitoring of civil projects involves the utilization of diverse sensors. Nevertheless, accurately assessing the actual condition of a structure can pose challenges due to the existence of anomalies in the collected data. Abnormalit...

The ability to conduct automated operational modal analysis is essential for enabling real-time structural health monitoring without human intervention. Such automation remains a significant challenge due to the complexity of processing large datasets and the necessity of setting multiple user-defined thresholds. This study introduces a novel metho...

The using of flat slab systems is a common structural solution for residential and commercial buildings as they are a cost-effective structural solution that simplifies and speeds up the construction phase. However, the flat slab systems have complex behavior, particularly in the slab–column connection zones, because of punching shear. Therefore, t...

On February 6, 2023, two major earthquakes with magnitudes 7.7 and 7.6 Mw struck within 9 h near the towns of Pazarcık and Elbistan, respectively, in the province of Kahramanmaraş, Türkiye. The main regions affected by these earthquakes were 11 provinces of Türkiye, home to approximately 16% of the country’s total population. Carrying out rapid and...

In this study, the changing of dynamic characteristics of masonry arches at varying geometric parameters and temperature histories was investigated through a combination of experimental and numerical methods. First, the dynamic characteristics of laboratory-built arch models were determined both pre- and post-high-temperature test using ambient vib...

Fire incidents in automated vehicle parking (AVP) structures are rare, yet the impact of such incidents on the structural integrity of these systems is crucial for design considerations. Although sprinklers are recognized for their effective fire suppression in various settings, the effectiveness of sprinkler systems in AVP structures fire incident...

This study presents an experimental evaluation of fiber-reinforced polymer (FRP) strengthening in concrete specimens damaged by exposure to high temperatures. For this purpose, sixty cylindrical concrete specimens were produced. Specimens exposed to temperatures of 200 • C, 400 • C, and 600 • C were strengthened using carbon and glass FRP fabrics i...

Evaluating adiabatic surface temperature (AST) as the thermal response of fire-exposed bridge elements is a complex and time-consuming task. Correspondingly, this study streamlined fire dynamic simulator (FDS) and machine learning (ML) in a surrogate model to predict the AST of suspension bridge tower. For this, various FDS simulations were conduct...

In the year 1999, two devastating earthquakes (Mw 7.4 Kocaeli earthquake in August and Mw 7.2 Düzce earthquake in November) occurred in Northwest Türkiye. These two earthquakes led to a very large number of casualties and building collapses. When the 1999 earthquakes occurred, most of the structures in the earthquake-impacted region were not design...

Seismic performance evaluation of masonry structures is of paramount importance for ensuring the safety and resilience of buildings in earthquake-prone regions. There are limited number of studies on pumice elements in the literature. In addition, there are almost no studies investigating the earthquake behavior of pumice masonry building as a whol...

This study investigates the seismic behavior of long-span prestressed concrete box-girder bridges subjected to long-duration (LD) ground motions and spectrally equivalent near-fault (NF) and far-fault (FF) short-duration ground motions. For this purpose, the Kömürhan and Gülburnu Highway Bridges built with the balanced cantilever method using prest...

Conducting a structural fire analysis for automated steel parking structures present a complex challenge due to the vulnerability of steel structures to high-temperature exposure, the unpredictability of fire source locations, and the enhanced thermal loading due to high concentration of vehicles in a compact area. This study conducted a performanc...

Records of bridge fire incidents illustrate that bridge fires can have catastrophic consequences. The severity of these fires can be influenced by various factors such as bridge type, vehicle size, and wind. Contrary to building fires that have been extensively studied, scant attention has been paid to bridge fires and more specifically fire exposu...

This paper presents verification of the numerical model of masonry infill walls against the experimental results. Three cases are investigated: an undamaged model, a damaged model, and a carbon fiber-reinforced polymer (CFRP) strip. ABAQUS commercial finite element model (FEM) software was used in the modeling. Nonlinear behavior as well as crackin...

Construction techniques and building materials are greatly affected by traditions and local factors which makes each historical structure unique. Therefore, the structural evaluation of these structures should be a structure-specific evaluation rather than a common-precise acceptance. The first step is to set the aim of the evaluation such that it...

This study focuses on the identification of collapsed buildings in satellite images after earthquakes through deep learning-based image segmentation models. The performance of four different architectures, namely U-Net, LinkNet, FPN, and PSPNet, was evaluated using various performance metrics, such as accuracy, precision, recall, F1 score, specific...

This study presents an innovative and automated methodology for assessing damage levels in masonry structures following earthquakes, utilizing a deep learning-based segmentation approach. Central to this research is the use of a U-Net convolutional neural network (CNN) model, which facilitates automated damage detection with a focus on smartphone-e...

The present study contributes to enriching the sparse literature on the seismic analysis of historical masonry buildings through field observations and advanced computational tools. To do this, the findings from field observations in the area affected by the February 6th, 2023, Kahramanmaraş earthquakes (Mw = 7.7 and Mw = 7.6) are evaluated to poin...

This paper offers a structural assessment of the historical Santa Maria Church and its Guesthouse building in Trabzon, Turkey. This process involves non-destructive experimental investigation using ambient vibration test and numerical evaluation using finite element method. Finite element model updating procedure was employed for the buildings usin...

The efficient and precise identification of cracks in masonry stone structures caused by natural or human-induced factors within a specific region holds significant importance in detecting damage and subsequent secondary harm. In recent times, remote sensing technologies have been actively employed to promptly identify crack regions during repair a...

This study presents large-scale shake table test results to investigate the responses of RC structures exposed to earthquake-induced pounding effects. The effects of pounding on structural responses and damage were discussed by comparing the experimental results with and without interaction. In the shake table test, ½ scaled two-story RC specimens...

Masonry structures, characterized by their brittle behavior, are susceptible to easy damage when subjected to external forces. Especially, soil-structure interaction problems are important factors which may cause deterioration or complete loss of structural integrity in the masonry structures. For this reason, different settlements and deformations...

In recent years, unfavourable actions such as excessive deflection, uneven settling of the soil beneath foundations, structural loads, deterioration of materials, poor maintenance, landslides, deficiency in the initial builder's structural knowledge, flood, earthquake and explosive blast have led to the collapse of structures and loss of human life...

Energy consumption is rising alongside the associated danger of fire due to the increased industrialization and urbanisation of previously rural areas. An example of a building that is predisposed to fire has a furnace on the bottom floor, one that is used in the production of iron and steel, or thermal power plants. It’s difficult, time-consuming,...

Parametric modeling allows a new form to be obtained automatically by changing parameters with variable properties without the need to redraw a geometric form. This situation shortens the project design time and enables the most suitable model to be put forward in a short time. In this paper, it is aimed to explain the importance and latest situati...

Masonry constructions are edifices created through the amalgamation of fragile substances like stones, bricks, and pumice utilizing mortar. The masonry structures, which do not show the desired ductile behavior against dynamic effects, show a brittle behavior. In scenarios like earthquakes, when masonry structures surpass their load-bearing capabil...

The past two decades have witnessed rapid advances in the use of fiber-reinforced polymer (FRP) composites in different engineering fields. Advantages such as high strength-to-weight ratio, corrosion resistance, and tailority have led to immense interest in the use of FRPs in wide spectrum repair and strengthening of structures. Despite their many...

On February 6, 2023, two major earthquakes (Mw 7.7 and Mw 7.6) occurred in the province of Kahramanmaraş in southern Türkiye at 9-h intervals, causing a lot of loss of life and destruction in the region where approximately 16% of the country’s population lives. This study provides a comprehensive summary of common structural deficiencies that occur...

This study addresses the effects of different initial residual displacements of isolators on the seismic vulnerability of isolated reinforced concrete (RC) buildings with Lead Rubber Bearing (LRB). Based on the ground motion intensity measure chosen as peak ground acceleration (PGA), fragility functions were derived using a lognormal cumulative dis...

Purpose: This study aims to predict crack initiation, propagation, and subsequent nonlinear structural behavior in the Koyna dam using a combination of FEM solver and XFEM potential. A 1:150 Scale Two-dimensional dam model for crack prediction using XFEM without Initial Crack Propagation in ABAQUS 2019 Software" Study design/methodology/approach: T...

Purpose: A validated finite element model is used in this study to investigate stone masonry models and evaluate the efficacy of employing carbon fiber reinforced polymers (CFRP). The primary goal of the project is to provide at least, an accurate finite element model utilizing ABAQUS software for accurate and detailed analysis, while also addressi...

The interest in damage identification methods has increased significantly in recent years due to the rising demand for structural health monitoring of structures. This study presents an enhanced version and validation of a recently introduced method for damage detection, localization and quantifying damage using vibration data. The method is valida...

In this paper, the aim is to detail the newly introduced method, which is based on the calculation of modal participation ratio, in damage detection and assessment. For this aim, a four-story reinforced concrete building model is employed for numerical application. The method is evaluated for two damage scenarios, namely, single story and cumulativ...

Historical masonry structures, which constitute an important part of the historical heritage, exhibit brittle behavior under tensile stresses due to earthquakes or soil movements/settlements. Therefore, they are sensitive to deformation. The soil–structure interaction problems play an important role in the damage to historical masonry structures. D...

In this study, engineering software for the calculations of the strengthening applications of reinforced concrete (RC) load-bearing elements with Fiber Reinforced Polymer (FRP) composite materials is developed. This software is developed to increase the axial compression strength and ductility capacity of columns and improve the shear capacity of b...

Two major earthquakes occurred on the Eastern Anatolian Fault Line (EAF) on February 6, 2023, with an interval of nine hours. These earthquakes, measuring Mw 7.7 and Mw 7.6, were centered in the districts of Pazarcık and Elbistan in the province of Kahramanmaraş. They directly affected 11 provinces (Kahramanmaraş, Hatay, Adıyaman, Osmaniye, Gaziant...

6 Şubat Kahramanmaraş Depremlerine İlişkin Saha Gözlem ve Değerlendirmeleri

Extensive research on fiber-reinforced polymer (FRP) composites has led to the presumption that this material is an effective solution for repairing and strengthening the reinforced concrete (RC) elements. The use of FRP significantly enhances the carrying capacity of elements under structural loads. However, the poor fire performance of this mater...

Cultural heritage structures reflect the lifestyles and creative aspects of our ancestors. Indeed, they contain the cultural roots of today’s societies and connect the past to the present. There is no doubt that architectural and structural evaluation plays important role in the conservation of these structures for the future. This paper focuses on...

A strong earthquake with a moment magnitude of [Formula: see text].9 according to the Disaster and Emergency Management Authority (AFAD) occurred at 04:08 local time on November 23, 2022, in Gölyaka district of Düzce province that is located in the Western Black Sea region of Turkey. The earthquake with a shallow focus is 0.82 km away from Kemeryan...

This repository captures some of the images and damage conditions identified by the StEER VAST while scanning social media and other online sources after the Mw 6.1 Duzce, Turkey Earthquake. The examples included in these slides augment what is presented in the joint PVRR report for this event (DesignSafe Project PRJ-3800). None of the data in this...

An earthquake occurred in Duzce, Turkey on Nov. 23, 2022 with magnitude of 6.1 and a depth of 10.0 km. The region has been struck by several destructive earthquakes in the past decades. The vast majority of the buildings in the region affected by the earthquake, including government and school buildings, have been either retrofitted or rebuilt afte...

Timber, one of the oldest structural materials, is an essential material in the construction of traditional structures due to its undeniable advantages. However, wood is sensitive to environmental effects, and hence, historical timber structures experience various degradations and destructions during their service life. This highlights the necessit...

On November 23, 2022, at 04:08 local time, the Gölyaka district of Düzce, which is located in the west of the Black Sea Region of Turkey, struck an earthquake with a magnitude of Mw = 5.9. A total of 181 reinforced and masonry buildings were severely damaged due to the earthquake and it is reported that need to be demolished urgently throughout the...

Historical masonry structures have an important place in cultural heritage. Therefore, maintenance of these structures should be made periodically to prevent natural and manmade hazards. The maintenance of these structures is divided into two parts, namely experimental and numerical applications. Experimental, especially non-destructive methods are...

The fragility and capacity of historical structures can be evaluated under seismic loads with the help of a rigid-base assumption by neglecting soil–structure interaction effects. However, this approach may not be accurate because earthquake waves reach the structure by spreading through a soil medium. Wave propagation, soil amplification, and defo...

Industrial structures built with different materials and methods play an important role in the sector with development of industry and increase in energy need. Many parameters are considered in the design and application phase of industrial structures to provide service for many years. The aim of this study is to examine dynamic behavior of reinfor...

This article presents a study about new type mechanical systems effectiveness to reduce the coupling beam damages using non-destructive experimental measurement results. Five half-scaled reinforced concrete (RC) coupling beams were constructed to be examined in laboratory conditions. In the first three test specimens, different rebar configurations...

The Bosphorus Suspension Bridge, which connects the Asian and European sides, has a geopolitical importance in terms of its location, and has also been integrated with Istanbul. The bridge has a main span of 1074 m, and it had inclined hanger configuration until recently. On January 2004, a hanger-to-deck connection close to European side tower was...

Masonry structures are one of the structures most affected by earthquakes. In addition, since masonry structures constitute a large part of the building inventory, it is important to determine the dynamic characteristics of these structures. The present study is aimed to evaluate the seismic performance of a half-scale hollow brick unreinforced mas...

In this study, the dynamic responses and damage to buildings subjected to explosions were investigated. A total of 72 blasting scenarios were considered by utilizing the TNT explosive weights, concrete strengths, and openings in the facades of buildings. The blast analyses are performed using six TNT weights, six concrete strengths, and two opening...

Structural assessment of a historical building requires many different applications, such as in-situ observations, in-situ measurements such as minor destructive or non-destructive tests and numerical analyses. Minor destructive and non-destructive tests such as ultrasonic tests and ambient vibration tests are used to collect data from the structur...

A deep learning-based image processing study was carried out to predict the post-fire safety of historical masonry structures. For this purpose, andesite stone and lime-based mortar, which are frequently used in historical structures, were selected as test samples and the samples were exposed to high temperatures (200°C, 400°C, 600°C and 800°C) at...

The dynamic parameters obtained depending on the existing structural properties, material properties, boundary and damage condition are quite effective on the behavior of the structures under the effect of dynamic loads. These dynamic parameters have characteristic features for each structure. In this study, the effect of damping ratio, which is on...

Engineering software running on object-oriented programming language has been extensively used in structural modeling past 20 years. Taking their ease of use and a large area of utilization into account, these software will be used by engineers. Moreover, a number of these software increases, and many enhancements take place. Considering the develo...

This paper is based on the the post-earthquake evaluation of two heavily damaged historic masonry mosques and the investigation of the effects of near-fault and far-fault ground motions on their seismic behaviors. The Hüsrev Pasha and Kaya Çelebi mosques, located in Van province, Turkey, were exposed to two devastating earthquakes (on October 23, 2...

This paper presents damage identification and localization in laminated composite beams including multiple cracks by automated model updating. For this aim, a cantilever beam made of glass/epoxy composite laminate under six simulated damage scenarios is considered. Experimental frequencies and mode shapes of the beam are validated with those of ANS...

Historical structures are vulnerable to effect of earthquake, wind, flood, fire, etc. Considering the active seismic resources owned Turkey, earthquakes especially important threats for historical structures. Therefore, the structural response of historical structures should be investigation under seismic effects. The most important factor in inves...

Damages to structures may occur due to construction defects during various stages such as design, construction, and operation phases, or due to natural disasters during their lifetime. The Operational Modal Analysis (OMA) method enables engineers to experimentally determine the changes in dynamic characteristics of the structures that resulted from...

This work aims to experimentally show the effectiveness of annular cylindrical tuned liquid dampers (ACTLDs) on the classical tuned liquid column dampers (TLCDs) under the effect of inclined ground motion. For experimental measurements, a single-story model structure constituted by two plates at the top and bottom connected by four columns was cons...

In this paper, modal parameters of the Eynel steel arch highway bridge are identified and the fatigue behavior of the bridge is investigated. Modal parameters were extracted from three ambient vibration tests carried out over the period since the bridge came into service. The bridge became operational in 2009, and experimental measurements were tak...

Since ancient times, shelter has been one of the most basic needs of human beings. This basic need has been tried to be met by using different local materials considering both economic conditions and security understanding. The so-called “Hımış” houses formed by filling the gaps between the timber frames with masonry elements reflect the typical fe...

This study presents the experimental and numerical assessment of natural frequencies and corresponding mode shapes of cross-laminated timber (CLT) beams subjected to a series of damage cases. To this aim, two different cantilever CLT beams consisting of three layers are considered. Damages on the beam are represented by transversal notches (cracks)...

A great number of reinforced concrete building structures were damaged or collapsed during the earthquake that hit Sivrice district of Elazığ city located in the southwest of the Eastern Anatolia Region of Turkey on January 24, 2020. Magnitude of the earthquake were announced as [Formula: see text] and [Formula: see text] by Kandilli Observatory &...

Fire hazard is a high impact threat to human life and engineering structures, which may result in significant loss of strength and huge damage to building components. In order to determine the strength and durability of structural elements after the fire and consequently to clarify the serviceability status for planning the necessary maintenance st...

This paper presents results of an experimental study that focuses on monitoring changes in dynamic characteristics of a damaged and retrofitted two-story reinforced concrete (RC) building model with poor detailing. In the study, ambient vibration tests are performed via four test setup protocols in order to monitor changes in dynamic characteristic...

This paper investigates the optimal sensor placements and capabilities of this procedure for dynamic characteristics identification of arch dams. For this purpose, a prototype arch dam is constructed in laboratory conditions. Berke arch dam located on the Ceyhan River in city of Osmaniye is one of the highest arch dam constructed in Turkey is selec...

Cultural heritage buildings are valued in contemporary societies as they reflect the lifestyles and creative achievements our predecessors. For this reason, many countries have introduced regulations to ensure conservation of their historic buildings for the future, permitting minimal changes only to their original structure and characteristics. Th...